Sulfides are commonly encountered in various industrial products and processes, including cooling water, paper manufacturing, oil field flood water, and the like. While a number of compounds are currently available which are effective as scavengers for sulfides, none is completely effective in all situations, and may also have undesirable characteristics in terms of handling, toxicology, spectrum of activity, cost and the like.
For example, a number of sulfide scavengers are reported in the literature and are indicated to be effective for removing sulfides from water and other fluids. Most recently, U.S. Pat. No. 4,680,127 which issued in 1987 to Edmondson, discloses the use of glyoxal for reducing the amount of hydrogen sulfide in aqueous or wet gaseous media. This patent also provides a review of the prior art in this area, and particularly the utility of acrolein. The patentees refer to U.S. Pat. No. 3,459,852 which issued to Roehm and is directed to the use of acrolein and to U.S. Pat. No. 1,991,765 which disclosed the use of formaldehyde for the same purpose.
It is stated in the Edmondson patent that "acrolein is more expensive than formaldehyde as well as extremely toxic and dangerous to handle". It is also indicated that "glyoxal approaches the hydrogen sulfide scavenging rate of acrolein without the constraining handling problems presented by the use of acrolein". Indeed, acrolein has been used for some time to reduce sulfide concentrations in the production of oil and gases, but its use has been greatly hampered by problems of handling and toxicity. In contrast, the compounds employed in the process of the present invention are at least the functional equivalent of acrolein, but have the added advantage of being extremely rapid and efficient scavengers of sulfide from fluids and yet do not present the toxicity or handling problems of previous scavenger compounds, such as acrolein.
It is known that corrosion can occur in pipelines from oil wells due to the presence of hydrogen sulfide and its salts. Droplets of water can form on the interior of gas pipe lines and in the presence of sulfides can give rise to corrosive conditions. Thus, in the recovery of natural gases and in oil wells which utilize flooding operations, sulfide scavenger compounds are sometimes used to prevent or at least mimimize corrosion. Moreover, it is well known that hydrogen sulfide is toxic and hence its removal is desirable.
In U.S. Pat. No. 3,024,192, which issued Mar. 6, 1962 to E. O. Bennett et al there is disclosed an improved method in a flooding program for the recovery of oil from oil bearing subterranean formations, which utilze a halonitroalkanol such as 2-bromo-2-nitro-1,3-propandiol, 2-chloro-2-nitro-1-butanol and the like. However, the compounds are used to inhibit the growth of sulfate-reducing bacteria and not as scavengers for sulfides. Moreover, there are many instances wherein bacteria are not present in any appreciable amount but it is desired to remove sulfides present in a fluid.
Accordingly, one or more of the following objects will be achieved by the practice of the present invention. It is an object of this invention to provide a process for the removal of sulfides from solids and fluids. Another object of this invention is to provide a process for the removal of sulfides and sulfide salts from liquid and gases, particularly in industrial operations. A further object is to remove sulfides from solids, such as sulfide deposits on the inner surfaces of pipes. A still further object of this invention is to provide a process which avoids the use of toxic and dangerous chemicals such as acrolein in the removal of sulfides. A still further object of this invention is to provide a process for removal of sulfide which utilizes certain halonitroalkanols. Another object is to provide a process which employs 2,2-dibromo-2-nitroethanol. A further object is to provide formulations useful for sulfide removal. Another object is to provide a method for scavenging sulfides which are present in industrial water cooling systems. It is also an object of this invention to provide a method for removing sulfides in industrial processes used in the production of pulp and paper. A still further object of this invention is to provide a method for using the halonitroalkanols compositions in the treatment of water employed in oil well flooding operations. These and other objects will readily become apparent to those skilled in the art in the light of the teachings herein set forth.